Oxygen therapy administration methods and related apparatus

ABSTRACT

Methods and apparatus for administering oxygen therapy, and particularly high-flow oxygen therapy is disclosed herein. A respiratory monitoring system may non-invasively determine average peak inspiratory flow rate of a patient based on biofeedback response received from the patient. Medical air, oxygen, or a combination of both may be delivered to the patient at a flow rate equal to greater than the determined average peak inspiratory flow rate of the patient to meet or exceed inspiratory demand of the patient. Fraction of oxygen inspired by the patient may be determined based on the average peak inspiratory flow rate and may be adjusted through high-flow oxygen therapy meeting inspiratory demand to prevent entrainment of ambient air or through low-flow oxygen therapy by accounting for entrainment of ambient air based on the average peak inspiratory flow rate to address medical needs of the patient.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/063,380, filed on 2020 Oct. 5, which claims the benefits of U.S.Prov. Pat. App. Ser. No. 62/988,888, filed on 2020 Mar. 12, the entirecontents of which are expressly incorporated herein by reference.

STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT

Not applicable.

BACKGROUND

The various aspects and embodiments described herein relate to oxygentherapy in general, and high-flow oxygen therapy in particular, where abreathing gas, such as compressed air or oxygen, is delivered to apatient at a flow rate high enough to meet or exceed the patient'sinspiratory demand.

Individuals, or patients, may require assistance with respiration, forexample, to stabilize breathing and control blood gases. In suchcircumstances, high-flow oxygen therapy may be suitable for patients,where oxygen is delivered to the patient at a flow rate higher than thatdelivered in traditional oxygen therapy. However, flow rate of oxygendelivered in high-flow oxygen therapy may often not be high enough tomeet or exceed inspiratory demand of patients due to lack of a simple,non-invasive, and accurate way to identify the correct flow rate ofoxygen that meets or exceeds inspiratory demand. When flow rate ofoxygen is not high enough to meet or exceed inspiratory demand, patientswill entrain ambient air along with the delivered oxygen to make up forthe insufficient oxygen flow, causing healthcare professionalsadministering high-flow oxygen therapy to be blind to the fraction ofoxygen inspired by the patients, a vital metric of oxygenation.

Accordingly, there is a need in the art for an improved method anddevice to identify and deliver the correct flow rate of oxygen thatmeets or exceeds inspiratory demand of patients, and measure fraction ofoxygen inspired by patients.

BRIEF SUMMARY

Methods and related apparatus for administering oxygen therapy, andparticularly high-flow oxygen therapy is disclosed herein. A respiratorymonitoring system may non-invasively receive biofeedback response from apatient's breathing in and out to determine the patient's average peakinspiratory flow rate. High-flow oxygen therapy may be administered bydelivering breathing gas to the patient at a flow rate equal to orgreater than the patient's average peak inspiratory flow rate to meet orexceed the patient's inspiratory demand. The breathing gas delivered tothe patient may be adjusted in terms of its oxygen percentage. Theoxygen percentage of the breathing gas may be adjusted to deliver theproper fraction of inspired oxygen to the patient. Fraction of oxygeninspired by the patient may be adjusted to address medical needs of thepatient by controlling the oxygen concentration in the breathing gasoutputted from a breathing gas source and setting the flow rate of thebreathing gas to equal to or greater than the average peak inspiratoryflow rate so that the patient does not entrain ambient air. Low bloodoxygen saturation may be treated by increasing the fraction of oxygeninspired by the patient through high-flow delivery of breathing gashaving an oxygen concentration greater than that of ambient air. In someinstances, low-flow oxygen therapy, delivering breathing gas to thepatient at a flow rate less than the patient's average peak inspiratoryflow rate, may be administered to allow the patient to entrain ambientair to control the fraction of inspired oxygen.

In accordance with one embodiment of the present disclosure, there maybe a method of administering high-flow oxygen therapy. The method mayinclude providing a respiratory monitoring system. The respiratorymonitoring system may have a computer and at least one biofeedbacksensor. The computer may have a frame. At least one display and at leastone processor may be coupled to the frame. The at least one biofeedbacksensor may be configured to be attachable to a patient and electricallycouplable to the computer. The biofeedback sensor may receivebiofeedback response through the patient's torso. The respiratorymonitoring system may either be configured to measure minute volume andrespiratory rate or tidal volume of the patient based on the biofeedbackresponse. The method may also include providing an air-oxygen blender.The air-oxygen blender may output air deliverable to the patient by atube. The tube may be attachable to the patient and to the air-oxygenblender. The method may also include attaching the at least onebiofeedback sensor to the computer of the respiratory monitoring systemand to the patient. The method may also include reading the minutevolume and the respiratory rate. Alternatively, the step may be readingthe tidal volume outputted by the at least one display of therespiratory monitoring system in communication with the computer. Themethod may also include determining average peak inspiratory flow ratebased on the minute volume and the respiratory rate. Alternatively, thestep may be determining average peak inspiratory flow rate based on thetidal volume. The method may also include adjusting flow rate of air tobe delivered to the patient from the air-oxygen blender to equal to orgreater than the determined average peak inspiratory flow rate to meetor exceed the patient's inspiratory demand.

The respiratory monitoring system may be further configured to determinethe average peak inspiratory flow rate and output the average peakinspiratory flow rate via the at least one display of the respiratorymonitoring system. The step of determining average peak inspiratory flowrate may comprise reading the average peak inspiratory flow rateoutputted by the at least one display of the respiratory monitoringsystem.

The method may also include attaching the tube to the patient and to theair-oxygen blender and delivering the air to the patient. The step ofdelivering the air to the patient may comprise delivering the air to thepatient at the adjusted flow rate until blood oxygen saturation of thepatient reaches a desired percentage. Alternatively, the step ofdelivering the air to the patient may comprise delivering the air to thepatient at an unadjusted flow rate, and then at the adjusted flow rate.The method may also include changing oxygen concentration in the airdelivered by the air-oxygen blender to achieve a desired fraction ofoxygen inspired by the patient. The method may also include determiningfraction of oxygen inspired by the patient based on the average peakinspiratory flow rate, an unadjusted flow rate of the air beingdelivered to the patient, concentration of oxygen in the air beingdelivered to the patient, and flow rate of ambient air inspired by thepatient. The method may also include determining fraction of oxygeninspired by the patient based on the adjusted flow rate of the air beingdelivered to the patient and concentration of oxygen in the air beingdelivered to the patient. The method may also include decreasing theadjusted flow rate of air delivered to the patient from the-air oxygenblender as the fraction of oxygen inspired by the patient increases.

According to another aspect of the present disclosure, there may be amethod of administering high-flow oxygen therapy. The method may includeproviding a respiratory monitoring system. The respiratory monitoringsystem may have a computer and at least one biofeedback sensor. Thecomputer may have a frame. At least one display and at least oneprocessor may be coupled to the frame. The at least one biofeedbacksensor may be configured to be attachable to a patient and electricallycouplable to the computer. The at least one biofeedback sensor mayreceive biofeedback response from the patient. The respiratorymonitoring system may either be configured to measure minute volume andrespiratory rate or tidal volume of the patient based on the biofeedbackresponse. The method may also include providing a breathing gas source.The breathing gas source may output breathing gas deliverable to thepatient by a tube. The tube may be attachable to the patient to thebreathing gas source. The method may also include attaching the at leastone biofeedback sensor to the computer of the respiratory monitoringsystem and to the patient. The method may also include attaching thetube to the patient and to the breathing gas source. The method may alsoinclude reading the minute volume and the respiratory rate.Alternatively, the step may be reading the tidal volume outputted by theat least one display of the respiratory monitoring system incommunication with the computer. The method may also include determiningaverage peak inspiratory flow rate based on the minute volume and therespiratory rate. Alternatively, the step may be determining averagepeak inspiratory flow rate based on the tidal volume. The method mayalso include adjusting flow rate of breathing gas to be delivered to thepatient from the breathing gas source to equal to or greater than thedetermined average peak inspiratory flow rate. The method may alsoinclude adjusting oxygen concentration of the breathing gas based on adesired fraction of oxygen to be inspired by the patient. The method mayalso include delivering the breathing gas to the patient at the adjustedflow rate and at the adjusted concentration of oxygen to achieve thedesired fraction of oxygen to be inspired by the patient.

The respiratory monitoring system may be further configured to determinethe fraction of oxygen inspired by the patient and output the fractionof oxygen inspired by the patient via the at least one display of therespiratory monitoring system. The method may also include inputting theadjusted flow rate of the breathing gas being delivered to the patientinto the respiratory monitoring system. The step of determining thefraction of oxygen inspired by the patient may comprise reading thefraction of oxygen inspired by the patient outputted by the at least onedisplay of the respiratory monitoring system.

The oxygen concentration of the breathing gas may be equal to or greaterthan 21%. The breathing gas may be heated, humidified, and delivered tothe patient through a nasal cannula.

The method may also include decreasing the adjusted flow rate as thefraction of oxygen inspired by the patient increases. Alternatively, themethod may also include decreasing the concentration of oxygen of thebreathing gas delivered to the patient as the fraction of oxygeninspired by the patient increases.

According to another aspect of the present disclosure, there may be arespiratory monitoring system used in administering oxygen therapy. Therespiratory monitoring system may have a computer and at least onebiofeedback sensor. The computer may have a frame. At least one displayand at least one processor may be coupled to the frame. The at least onebiofeedback sensor may be configured to be attachable to a patient andelectrically couplable to the computer. The at least one biofeedbacksensor may receive biofeedback response from the patient. The at leastone processor may be configured by program instructions to determineminute volume and respiratory rate. Alternatively, the at least oneprocessor may be configured by program instructions to determine tidalvolume in real time. The at least one processor may be furtherconfigured by program instructions to determine average peak inspiratoryflow rate in real time based on the minute volume and the respiratoryrate. Alternatively, the at least one processor may be furtherconfigured by program instructions to determine average peak inspiratoryflow rate in real time based on the tidal volume. The at least onedisplay may be configured by program instructions to output thedetermined average peak inspiratory flow rate in real time.

The respiratory monitoring system may further include a sensorconfigured to detect flow rate of oxygen being delivered to the patientby an oxygen delivery system. The at least one processor may be furtherconfigured by program instructions to determine fraction of oxygeninspired by the patient in real time. The at least one display may befurther configured to output the determined fraction of oxygen inspiredby the patient in real time.

The at least one processor may be further configured by programinstructions to determine fraction of oxygen inspired by the patient inreal time based on the determined average peak inspiratory flow rate.

The at least one processor may be further configured by programinstructions to communicate with a microcontroller of an automatedoxygen delivery system to adjust flow rate of oxygen being delivered tothe patient to equal to or greater than the determined average peakinspiratory flow rate to meet or exceed the patient's inspiratorydemand.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the various embodimentsdisclosed herein will be better understood with respect to the followingdescription and drawings, in which like numbers refer to like partsthroughout, and in which:

FIG. 1 is a perspective view of a respiratory therapist administeringoxygen therapy to a patient;

FIG. 2 is a flow rate graph of a respiratory cycle of the patient ofFIG. 1 ;

FIG. 3A is a front view of a first embodiment of a computer of arespiratory monitoring system shown in FIG. 1 ;

FIG. 3B is a front view of a second embodiment of the computer of therespiratory monitoring system shown in FIG. 1 ;

FIG. 4A is a front view of a third embodiment of the computer of therespiratory monitoring system shown in FIG. 1 ;

FIG. 4B is a front view of a fourth embodiment of the computer of therespiratory monitoring system shown in FIG. 1 ;

FIG. 4C is a front view of a fifth embodiment of the computer of therespiratory monitoring system shown in FIG. 1 ;

FIG. 5A is a front view of a sixth embodiment of the computer of therespiratory monitoring system shown in FIG. 1 ;

FIG. 5B is a front view of a seventh embodiment of the computer of therespiratory monitoring system shown in FIG. 1 ;

FIG. 6 is an enlarged perspective view of a breathing gas source shownin FIG. 1 ; and

FIG. 7 is a diagram of a respiratory monitoring system, an automatedoxygen delivery system, and the patient of FIG. 1 interacting with eachother.

DETAILED DESCRIPTION

Referring now to the drawings, apparatuses for administering oxygentherapy, and particularly high-flow oxygen therapy, a breathing gassource 6 and a respiratory monitoring system 8 is shown. (see FIG. 1 )The respiratory monitoring system 8 may non-invasively receivebiofeedback response from a patient 2 breathing in and out to determineaverage peak inspiratory flow rate of the patient 2. (see FIG. 1 )High-flow oxygen therapy may be administered by delivering breathing gasto the patient 2 at a flow rate equal to or greater than the averagepeak inspiratory flow rate of the patient 2 to meet or exceedinspiratory demand of the patient 2. Also, the breathing gas is adjustedso the percent oxygen in the breathing gas is at the proper level forthe patient 2. In this way, the fraction of inspired oxygen for thatpatient 2 is controlled. Alternatively, the fraction of oxygen inspiredby the patient 2 may be controlled by accounting for air entrainmentbased on the difference of average peak inspiratory flow rate, the flowrate of breathing gas if the flow rate of the breathing gas is less thanthe average peak inspiratory flow rate, in other words low-flow and thepercentage of oxygen of the breathing gas.

Referring now to FIG. 1 , an individual, or the patient 2 receivingoxygen therapy is shown. Oxygen therapy may be administered by a secondindividual 4, who may be, for example, a respiratory therapist, aphysician, or a caregiver. Oxygen therapy may be administered in avariety of settings, including hospitals, rehabilitation centers,ambulances, and home care. The patient 2 may be hooked up to thebreathing gas source 6. The breathing gas source 6 may contain breathinggas having an oxygen concentration. In high-flow oxygen therapy, thebreathing gas source 6 may deliver the breathing gas at a flow rate upto 60 L/min. In contrast, breathing gas sources used in traditional, orlow-flow, oxygen therapy can generally deliver breathing gas at a flowrate up to 6 L/min.

The patient 2 may also be hooked up to the respiratory monitoring system8. The respiratory monitoring system 8 may have a computer 12 thatreceives biofeedback response via a biofeedback sensor or sensors fromthe patient 2. The respiratory monitoring system may be operative tomeasure minute volume (MV), respiratory rate (RR), inspiratory time (I),expiratory time (E), tidal volume (TV) of the patient 2. Minute volumeor MV is a volume of air inhaled by the patient in one minute.Respiratory rate or RR is the number of cycles of inhalation andexhalation taken by the patient in one minute. Inspiratory time is thetime in seconds that the patient spends inhaling air as depicted by 20in FIG. 2 . Expiratory time is the time in seconds that the patientspends exhaling air as depicted by 22 in FIG. 2 . Tidal volume or TV isthe volume of air breathed in by the patient in one breath.

These values (MV, RR, I, E, TV) can be used to calculate other valuesand displayed on the display 14. The biofeedback sensors may beelectrically coupled to the computer 12 to measure and display MV, RR,I, E, TV of the patient 2 on a display 14. In some embodiments, thebiofeedback sensor or sensors may be electrode pad or pads 10 thatdeliver current to the patient 2 and receive biofeedback response, whichmay be bioimpedance signals generated by torso 18 movement due tobreathing. In such embodiments, the electrode pads 10 may beelectrically coupled to the computer 12 via a cable 16 placed on thetorso 18 of the patient 2, to measure and display MV, RR, I, E, TV ofthe patient 2 on the display 14. The electrode pads 10 may have anadhesive back surface (not shown). In some embodiments, the electrodepads 10 may have the specifications of electrode pads sold as ExSpiron1Xi PadSets sold by Respiratory Motion, Inc. In such embodiments, theelectrode pads 10 may be positioned on the chest region of the patient 2to create an L-shape as shown in FIG. 1 . The electrode pads 10 may becentered on the chest and reach right below the neck and right under thepectoral muscle towards the armpit. In some embodiments, the electrodepads 10 may be generally positioned on the torso 18. In someembodiments, the respiratory monitoring system 8 may employ arespiratory inductance plethysmography device that measures changes inlung and/or abdominal volume during respiration. In such embodiments,the biofeedback sensors may be elastic belts (not shown) that have ashielded coiled wire sewn into them. The elastic belts may replace or beused in addition to the electrode pads 10. The elastic nature of thebelts may allow for expansion and contraction of the torso 18 while thewire may carry current to create a magnetic field (not shown). When thepatient 2 breathes, the torso 18 changes shape due to expansion andcontraction, and thus changes the shape of the magnetic field. Thisinduces an opposing current, which is measured as a change in frequencyof the applied current. Then, the signals generated, which is thebiofeedback response, may be received by the computer 12 of therespiratory monitoring system 8 to measure and display minute volume andrespiratory rate, or display tidal volume of the patient 2 on thedisplay 14.

Based on readings of the patient 2 from the respiratory monitoringsystem 8, the respiratory therapist 4 may determine average peakinspiratory flow rate of the patient 2. The readings may include minutevolume and respiratory rate of the patient 2 or the tidal volume of thepatient 2. Minute volume is the amount of breathing gas moved throughthe lungs of the patient 2 in one minute; respiratory rate is the numberof breaths the patient 2 takes per minute; and tidal volume is thevolume of breathing gas that is moved into and out of the lungs andairways in one breath (i.e., inhale once and exhale once). Peakinspiratory flow rate (PIFR) is the highest flow rate measured during aninspiratory period of a respiratory cycle of the patient 2. The desireddetermination to be made from the readings is average of the peakinspiratory flow rates observed in each inspiratory period within agiven time period. If breathing gas supplied to the patient 2 is at aflow rate equal to or greater than the determined average peakinspiratory flow rate, inspiratory demand of the patient 2 will be metif flow rate is equal to the average peak inspiratory flow rate, orexceeded if flow rate is greater than the average peak inspiratory flowrate. The respiratory therapist 4 may adjust the flow rate outputted bythe breathing gas source 6 to equal to or greater than the determinedaverage peak inspiratory flow rate. By doing so, the respiratorytherapist 4 may ensure that the inspiratory demand of the patient ismet.

Referring now to FIG. 2 , flow versus time graph of a respiratory cycleis shown. Periods 20 on the graph represent inspiratory periods of thecycle where the patient 2 (see FIG. 1 ) is breathing in oxygen. Periods22 on the graph represent expiratory periods of the cycle where thepatient 2 is breathing out oxygen. Peaks 24 a,b on the graph representpeak inspiratory flow of each inspiratory period 20. Inspiratory periods20 may have durations indicating how slow or how quick the inhalationwas for that period. For example, a shorter duration may indicate aquicker inhalation. Peak 24 a may represent the peak inspiratory flowrate of an inspiratory period where the patient 2 inhales like theynormally inhale. In an average adult, a normal peak inspiratory flowrate may be 30 L/min. Dashed lines 26 may indicate the average peakinspiratory flow rate of the patient 2. There may be an instance orinstances where the patient 2 inhales so that peak inspiratory flow rateis higher than the average peak inspiratory flow rate in a given timeperiod, for example, as indicated by peak 24 b. A higher than averagepeak inspiratory flow rate such as peak 24 b may occur if the patient 2quickly draws in oxygen as opposed to a generally consistent pace whenthe patient 2 is idle. Hence, peak 24 a may represent a peak inspiratoryflow rate that may be closer to the average peak inspiratory flow ratethan peak 24 b. When breathing gas is supplied to the patient 2 at aflow rate equal to or greater than the determined average peakinspiratory flow rate, the patient 2 may instantaneously entrain ambientair to meet inspiratory demand at peak 24 b. However, inspiratory demandwill still be met overall for a time period by delivering breathing gasat the average peak inspiratory flow rate of that time period.Delivering breathing gas at a flow rate above the average peakinspiratory flow rate may further mitigate entrainment of ambient air atpeaks such as 24 b. However, adjusting the flow rate to only slightlyabove the average peak inspiratory flow rate, preferably between 0.5 to6 L/min, more preferably between 0.5 to 3 L/min, is desirable to providea comfortable delivery to the patient 2.

Referring back to FIG. 1 , the respiratory therapist 4 may determine afraction of oxygen inspired by the patient 2 based on the determinedaverage peak inspiratory flow rate. Knowing the fraction of oxygeninspired by the patient 2 may help ensure the patient 2 is receiving theright amount of oxygen; neither too much nor too little. The respiratorytherapist 4 may increase fraction of oxygen inspired by the patient 2 toa desired percentage by setting the flow rate to equal to or greaterthan the determined average peak inspiratory flow rate. When the flowrate is adjusted as such, the patient 2 may have no need to consistentlyentrain ambient air, which generally has an oxygen concentration of 21%.Hence, the fraction of oxygen inspired by the patient 2 may increasefrom 21% when breathing gas with higher oxygen concentration isdelivered at the adjusted flow rate while the patient 2 has negligibleor no need to entrain ambient air. If the fraction of oxygen inspired bythe patient 2 reaches or exceeds a desired fraction of inspired oxygen,the flow rate of the breathing gas may be lowered. The lowered flow rateof the breathing gas may, stop, or counter the increase of fraction ofinspired oxygen. In some embodiments, the flow rate of the breathing gasmay be lowered to below the average peak inspiratory flow rate, orlow-flow, to allow the patient 2 to entrain air. In such embodiments,the breathing gas may have an oxygen concentration up to 100%, and thedifference of the average peak inspiratory flow rate and the flow rateof breathing gas may be accounted for flow rate of ambient air at 21%oxygen.

Increasing the fraction of oxygen inspired by the patient 2 may increaseblood oxygen saturation of the patient. Generally, an average healthyadult may have a bloody oxygen saturation between 94% to 99%. However,if the patient 2 is suffering from low blood oxygen saturation, orhypoxemia, where the blood oxygen saturation is 90% or below, increasingthe fraction of oxygen inspired by the patient 2 may increase bloodoxygen saturation to between 94% to 99%. For example, bronchiectasis maybe a respiratory illness where hypoxemia may be treated by high-flowoxygen therapy administered at or above the average peak inspiratoryflow rate. In contrast, administering high-flow oxygen therapy withoutknowing the average peak inspiratory flow rate of the patient 2 wouldcreate the risk of not meeting or exceeding the inspiratory demand ofthe patient and cause the patient 2 to entrain ambient air with 21%oxygen concentration. Similarly, administering low-flow oxygen therapywithout knowing the average peak inspiratory flow rate of the patient 2would eliminate the possibility of accounting for ambient airentrainment in determining and regulating fraction of inspired oxygen.Hence, there would be a risk of blood oxygen saturation not rising tothe desired range of between 94% to 99%. Determining average peakinspiratory flow rate and fraction of inspired oxygen of the patient 2will be discussed in greater detail below for FIGS. 3A-5B.

Referring now to FIGS. 3A-5B, the computer 12 of the respiratorymonitoring system 8 is shown. In some embodiments, the respiratorymonitoring system 8 may have the specifications of the ExSpiron 1Xirespiratory monitoring system sold by Respiratory Motion, Inc. Therespiratory monitoring system 8 (see FIG. 1 ) may have a processor orprocessors (not shown) that can be programmed to determine and display avariety of data related to the respiration of the patient 2 (see FIG. 1). The data may be received through the biofeedback sensors, which maybe the electrode pads 10 or the elastic belts (not shown) placed on thetorso 18 of the patient 2. (see FIG. 1 ) In some embodiments, theelectrode pads 10 may receive an electrical signal from the computer 12via the cable 16 and detect bioimpedance signals originating from thepatient 2. (see FIG. 1 ) In some embodiments, the elastic belts maycarry a current to the patient 2 and detect change in frequency of thecurrent. The bioimpedance signals or signals generated by the change incurrent frequency may reflect the movement of the torso 18 of thepatient 2 due to diaphragm expansion and contraction from breathing inand out. The bioimpedance signals or the signals generated by the changein current frequency may be converted to digital form, recorded, anddisplayed by the display 14 of the computer 12. In some embodiments, thecomputer 12 may communicate with a multi-parameter patient monitoringsystem (not shown) to further display the digitalized signals on adisplay of the multi-parameter patient monitoring system. Thecommunication between the computer 12 and the multi-parameter patientmonitoring system may require an adapter. By example and not limitation,the multi-parameter patient monitoring system may have thespecifications of IntelliVue manufactured by Philips. Also, by exampleand not limitation, the adapter may have the specifications ofIntelliVue MMX manufactured by Philips. The computer 12 may draw powerfrom a wall outlet or may have an internal battery for portability.

Referring now to FIG. 3A, the computer 12 may determine and displayminute volume, or minute ventilation, and respiratory rate on thedisplay 14. Minute volume is the amount of breathing gas moved throughthe lungs of the patient 2 (see FIG. 1 ) in a minute. It is a directmeasurement of the respiratory status of the patient 2. In someembodiments, the displayed minute volume may have a unit of volume, suchas L or mL. In some embodiments, the displayed minute volume may have aunit of volume over time, such as L/min, mL/min, L/s, or mL/s.Respiratory rate is the number of breaths the patient 2 takes perminute. In some embodiments, the displayed respiratory unit may haveunit of breath over time, such as breaths/min, or bpm. In someembodiments, the displayed respiratory unit may have a unit of breaths.The respiratory therapist 4 (see FIG. 1 ) may determine the average peakinspiratory flow rate by plugging the displayed minute volume and thedisplayed respiratory rate into the following formula where average peakinspiratory flow rate is indicated by APIFR, minute volume is indicatedby MV and respiratory rate is indicated by RR:

${APIFR} = {{MV} \times {\frac{60}{RR}.}}$The determined average peak inspiratory flow rate may have a unit ofvolume over time, such as L/min, L/s, mL/min, or mL/s. The flow rateoutputted by the breathing gas source 6 (see FIG. 1 ) may then beadjusted to equal to or greater than the determined average peakinspiratory flow rate.

Referring now to FIG. 3B, the computer 12 may determine and displaytidal volume on the display 14. Tidal volume is the volume of breathinggas that is moved into and out of the lungs and airways over a period oftime. Tidal volume has the following relationship with minute volume andrespiratory rate, where tidal volume is indicated by TV, minute volumeis indicated by MV, and respiratory rate is indicated by RR: MV=TV×RR.In some embodiments, the displayed tidal volume may have a unit ofvolume, such as L or mL. In some embodiments, the displayed tidal volumemay have a unit of volume over time, such as L/s, L/min, mL/min, ormL/s. The respiratory therapist 4 (see FIG. 1 ) may determine theaverage peak inspiratory flow rate by plugging the tidal volume into thefollowing formula where average peak inspiratory flow rate is indicatedby APIFR: APIFR=TV×60. The determined average peak inspiratory flow ratemay have a unit of volume over time, such as L/min, L/s, mL/min, ormL/s. In some embodiments (not shown), the computer 12 may measure andthe display 14 may display minute volume, tidal volume, and respiratoryrate. In such embodiments, the respiratory therapist 4 may choose to useany of the above formulas to determine average peak inspiratory flowrate. The flow rate outputted by the breathing gas source 6 (see FIG. 1) may then be adjusted to be equal to or greater than the determinedaverage peak inspiratory flow rate.

Referring now to FIGS. 4A-4B, the respiratory monitoring system 8 (seeFIG. 1 ) may be configured to determine and output average peakinspiratory flow rate of the patient 2 (see FIG. 1 ). The average peakinspiratory flow rate may be displayed on the display 14. The displayedaverage peak inspiratory flow rate may have a unit of volume over time,such as L/min, L/s, mL/min, or mL/s. The processor of the computer 12may compute the average peak inspiratory flow rate using the formula:

${APIFR} = {{MV} \times \frac{60}{RR}}$(or APIFR is equal to minute volume times 60 divided by respiratoryrate). An alternate formula for APIFR may be APIFR is equal to minutevolume times (inspiratory time plus expiratory time). In someembodiments, the processor of the computer 12 may additionally use theformula: MV=TV×RR. In some embodiments, minute volume and respiratoryrate may additionally be displayed. (see FIG. 4A) In some embodiments,tidal volume may additionally be displayed. (see FIG. 4B) In someembodiments, only average peak inspiratory flow rate may be displayed.(see FIG. 4C) In some embodiments, minute volume, respiratory rate, andtidal volume may additionally be displayed. (not shown) The respiratorytherapist 4 (see FIG. 1 ) may determine the average peak inspiratoryflow rate by checking the display 14. The flow rate outputted by thebreathing gas source 6 (see FIG. 1 ) may then be adjusted to be equal toor greater than the determined average peak inspiratory flow rate.

Referring now to FIGS. 5A-5B, respiratory monitoring system 8 (see FIG.1 ) may be configured to determine fraction of inspired oxygen of thepatient 2 (see FIG. 1 ). The determined fraction of inspired oxygen maybe displayed on the display 14. The displayed fraction of inspiredoxygen may be a percentage (%) or in decimals. In some embodiments,minute volume, respiratory rate, and average peak inspiratory flow ratemay additionally be displayed. (see FIG. 5A) In some embodiments, tidalvolume and average peak inspiratory flow rate may be additionallydisplayed. (see FIG. 5B) In some embodiments, minute volume, respiratoryrate, tidal volume and average peak inspiratory flow rate mayadditionally be displayed. (not shown) In some embodiments, only averagepeak inspiratory flow rate may additionally be displayed. (not shown)

The processor of the computer 12 may compute the fraction of inspiredoxygen based on average peak inspiratory flow rate, flow rate ofbreathing gas being delivered to the patient 2, and the concentration ofoxygen in the breathing gas being delivered to the patient 2. In someembodiments, the flow rate of breathing gas being delivered may bemanually inputted to the computer 12, for example, via a keypad,buttons, arrow keys, or a touch sensor of the display 14. (not shown) Insome embodiments, the flow rate of breathing gas being delivered may beprovided to the computer 12 through an electronic communication betweenthe computer 12 and the breathing gas source 6. In some embodiments, theflow rate of breathing gas being delivered may be equal to the averagepeak inspiratory flow rate, either inputted manually or determined bythe computer 12. In some embodiments, where flow rate of the breathinggas is equal to or greater than the average peak inspiratory flow rate,the processor may determine that fraction of inspired oxygen is equal tooxygen concentration of the breathing gas. In some embodiments, wherebreathing gas is being delivered to the patient 2 at a flow rate belowthe determined average peak inspiratory flow rate, the computer 12 mayaccount for ambient air entrained by the patient 2. The processor of thecomputer 12 may compute the flow rate of ambient air being entrained bythe patient 2 by calculating the difference between the average peakinspiratory flow rate and the flow rate of breathing gas beingdelivered. The processor of the computer 12 may then add the product ofthe flow rate of ambient air and the oxygen concentration of ambient air(21%) to the product of the flow rate of breathing gas being deliveredand the oxygen concentration of the breathing gas, and divide the sumfrom the average peak inspiratory flow rate to find the fraction ofoxygen inspired by the patient 2. In some embodiments, the respiratorytherapist 4 (see FIG. 1 ) may determine the fraction of inspired oxygenby performing the calculations mentioned above in discussing FIGS. 5A-5Bmanually. For example, the respiratory therapist 4 may do thecalculations by hand, refer to a chart or charts, or use a calculator.

Referring now to FIG. 6 , the breathing gas source 6 is shown. In someembodiments, the breathing gas source 6 may have the specifications ofhigh-flow nasal cannula devices, Optiflow or AIRVO 2, manufactured byFisher & Paykel. In some embodiments, the breathing gas source 6 mayhave the specifications of the high-flow nasal cannula device, VTU,manufactured by Vapotherm. The breathing gas source 6 may include theair-oxygen blender 28, also known as an oxygen proportioner. Theair-oxygen blender 28 may receive a medical air tank 30 and an oxygentank 32. The air-oxygen blender 28 may output gases from the medical airtank 30 and the oxygen tank 32 separately or as blended. In someembodiments, solely an oxygen tank 32 may be used in lieu of anair-oxygen blender. (not shown) Hence, the breathing gas delivered tothe patient 2 (see FIG. 1 ) may be medical air, oxygen blended withmedical air, or oxygen. The outputted breathing gas may have aconcentration of 21% to 100% oxygen. Preferably, the oxygenconcentration may be between 21% to 60%. Oxygen concentration greaterthan 60% delivered over an extended period of time, for instance morethan 24 hours, may result in complications, for example damage to lungsor eyes. The concentration of oxygen outputted may be adjusted byturning a front control knob 34.

Flow rate of the breathing gas outputted by the air-oxygen tank may beadjusted by turning a control knob 36. When the control knob 36 isturned, a flowmeter 38 may show the adjustment by reading the flow rateof the outputted breathing gas. In some embodiments, the breathing gassource 6 may be in wired or wireless (e.g., Bluetooth, Wi-Fi, orinfrared signal) electronic communication with the computer 12 of therespiratory monitoring system 8. In such embodiments, the breathing gassource 6 may relay breathing gas flow rate and or oxygen concentrationdata to the respiratory monitoring system 8. Also, in such embodiments,the respiratory monitoring system 8 may determine fraction of inspiredoxygen based on the flow rate and the oxygen concentration data. Flowrate of the breathing gas during oxygen therapy may be between 1 L/minto 60 L/min. During high-flow oxygen therapy, flow rate of the breathinggas may be between 10 L/min to 60 L/min; preferably, between 30 L/min to60 L/min. In some embodiments, the patient 2 (see FIG. 1 ) may receivebreathing gas at a flow rate between 1 L/min to 10 L/min initially, andthen receive high-flow therapy. In some embodiments, the patient 2 mayreceive breathing gas at a flow rate between 1 L/min to 60 L/min, andthen the flow rate may be adjusted so that the patient 2 receivesbreathing gas at a flow rate equal to or greater than the determinedaverage peak inspiratory flow rate. In some embodiments, the patient 2may receive breathing gas at a flow rate lower than the average peakinspiratory flow rate, for example below 30 L/min.

The breathing gas source 6 may also have a humidifier and heatercompartment 40. The humidifier and heater compartment 40 may humidifyand warm up the breathing gas before delivery to the patient 2. Theoutputted breathing gas from the air-oxygen blender may flow to thehumidifier and heater compartment through a tube 48. Humidified andheated breathing gas may provide comfort for the patient 2. The humidityand temperature may be displayed on a display 42 on the humidifier andheater compartment 40. The humidifier and heater compartment 40 may drawpower from a wall outlet or may have an internal battery forportability. (not shown) The humidifier and heater compartment 40 may bepowered on and off with a power button 42. The humidification andheating settings may be adjusted using buttons 44. A humidifierreservoir 46 may be connected to the humidifier and heater compartment40. The humidifier reservoir 46 may contain sterile water. Thehumidified and heated breathing gas may flow from the humidifier andheater compartment 40 to a nasal cannula 50 through a tube 52. In someembodiments, a Hudson mask, a Venturi mask, an anesthetic facemask, oranother suitable device appreciated by one of ordinary skill in the artmay replace the nasal cannula 50. (not shown) The nasal cannula 50 maybe inserted to the nostrils of the patient 2 for breathing gas delivery.(see FIG. 1 ) The nasal cannula 50 may create a seal within the nostrilsthat may let negligible or no ambient air into the nostrils. If noambient air is let into the nostrils, the patient 2 may entrain ambientair through the mouth if inspiratory demand of the patient 2 is not metnor exceeded. In some embodiments, the breathing gas source 6 may be amedical air tank or an oxygen tank having adjustable flow attached to atube that leads to a nasal cannula or another suitable deviceappreciated by one of ordinary skill in the art may replace the nasalcannula. (not shown)

Referring now to FIG. 7 , a diagram of a respiratory monitoring system54 in electrical communication with the patient 2 and electroniccommunication with a breathing gas source or an automated oxygendelivery system 56 delivering breathing gas to the patient 2 is shown.The respiratory monitoring system 54 may have the specifications andoperability of the respiratory monitoring system 8 shown in FIG. 1 ,except the additional capability to communicate, wired or wireless(e.g., Bluetooth, Wi-Fi, or infrared signal), with the automated oxygendelivery system 56. The automated oxygen delivery system 56 may have thespecifications and operability of the breathing gas source 6 shown inFIG. 1 , except the capability to automate breathing gas delivery basedon input directly received from the respiratory monitoring system 56.The computer 58 may relay average peak inspiratory flow determined byprocessor(s) 60 to a microcontroller 62 of the automated oxygen deliverysystem 56. The microcontroller 62 may then communicate with a breathinggas tank 64 of the breathing gas source to adjust flow rate of breathinggas outputted by the breathing gas tank 64 to equal to or greater thanthe average peak inspiratory flow rate to meet the inspiratory demand ofthe patient 2. In some embodiments, when flow rate greater than theaverage peak inspiratory flow rate is desired, how much greater it canbe may be preset. For example, a percentage of the average peakinspiratory flow rate or a specific rate increase may be added to theaverage peak inspiratory flow rate by the processor(s) 60 to determinethe desired flow rate. In some embodiments, the oxygen concentration ofthe breathing gas tank 64 may be preset. In some embodiments, the oxygenconcentration of the breathing gas tank 64 may be changed based on adesired fraction of inspired oxygen. In some embodiments, the computer58 may communicate with the microcontroller 62 to relay a desiredfraction of inspired oxygen to the microcontroller 62. Themicrocontroller 62 may then adjust the flow rate and/or theconcentration of oxygen of the breathing gas to achieve or maintain thefraction of oxygen inspired by the patient 2.

As discussed herein, the inspiratory demand of the patient was describedin relation to the average peak inspiratory flow rate. However, otherways of determining the inspiratory demands of the patent arecontemplated. For example, the inspiratory demands can expressed interms of the EstPIFR, last PIFR, greatest PIFR.

As discussed herein, the flow rate outputted by the breathing gas source6 may be adjusted by the system or a clinician to be equal to or greaterthan the determined average peak inspiratory flow rate. However, it isalso contemplated that the flow rate outputted by the breathing gassource 6 may be adjusted by the system or clinician to be equal to orgreater than a last peak inspiratory flow rate, a greatest peakinspiratory flow rate over a period of time (e.g., past one minute orone minute) or an estimated peak inspiratory flow rate.

In relation to the last peak inspiratory flow rate, it is contemplatedthat the system would calculate the inspiratory flow rate based on thelast inspiration of the patient and the system or clinician can adjustthe flow rate outputted by the gas source 6 to be equal or greater thansuch inspiratory flow rate. In relation to the greatest peak inspiratoryflow rate over a period of time, the system would record the peakinspiratory flow rate of each breath within a period of time, forexample, one minute. The system can detect the highest PIFR and thesystem or the clinician can adjust the flow rate outputted by the gassource 6 to be equal to or greater than the highest PIFR detected by thesystem.

Additionally, it is also contemplated that the flow rate outputted bythe breathing gas source 6 may be adjusted to be less than the last peakinspiratory flow rate, the greatest peak inspiratory flow rate over aperiod of time (e.g., past one minute or one minute) or an estimatedpeak inspiratory flow rate (EstPIFR).

The peak inspiratory flow rate (PIFR) may be calculated via the system(e.g., computer and the bioimpedance sensors or other bio feedbacksensors) with the following formula: PIFR is equal to minute volumetimes (inspiratory time plus expiratory time). Alternatively, peakinspiratory flow rate may be calculated with the following formula: PIFRis equal to (tidal volume times respiratory rate) times (inspiratorytime plus expiratory time).

The estimated peak inspiratory flow rate (EstPIFR) may be calculatedwith the following formula: EstPIFR=minute volume times “X” ifrespiratory rate is less than A or minute volume times “Y” ifrespiratory rate is greater than A. By way of example and notlimitation, X may be 3 and Y may be 2 or one whole number less than X,and A may be 30. The system with the biofeedback sensors would measurethe variables in the formulas provided herein and calculate/determinethe PIFR.

As discussed herein the flow rate outputted by the breathing gas source6 may be adjusted to be less than the various ways of determining thepeak inspiratory flow rate (e.g., APIFR, EstPIFR, PIFR). One purpose ofadjusting the flow rate to be lower than the various ways of determiningthe PIFR is to ween the patient off of supplemental oxygen.

In a clinical setting, it is beneficial to be able to know the fractionof inspired oxygen received by the patient. To do this, the inspiratorydemands of the patient may be measured with the respiratory monitoringsystem 8 disclosed herein. The respiratory monitoring system 8 maymeasure peak inspiratory flow rate of the patient by measuring one ormore of the MV, RR, I, E, TV of the patient. When the inspiratorydemands (i.e., any one of the PIFRs discussed herein) of the patient isknown, the fraction of inspired air received by the patient can bedetermined and the flow rate provided by the gas source to the patientcan be set. For example, the flow rate provided by the gas source of thesystem can be adjusted to supply blended oxygen at a flow rate greaterthan the PIFR of the patient. If so, then the fraction of inspiredoxygen is equal to the fraction of oxygen delivered to the patient bythe gas source 6. The clinician can adjust the oxygen percentage at thegas source since in this scenario the oxygen percentage delivered by thegas source is equal to the fraction of inspired oxygen received by thepatient. Based on the inspiratory demands of the patient, the cliniciancan set the system to deliver oxygen at a flow rate to achieve a targetfraction of inspired oxygen for a particular patient.

If the flow rate provided by the gas source is lower than the PIFR ofthe patient, then the system can calculate the fraction of inspiredoxygen and display the fraction of inspired oxygen received by thepatient. The flow rate provided by the gas source may be set to be lowerthan the PIFR of the patient when weening the patient off ofsupplemental oxygen. When the flow rate of gas provided by the gassource is less than the inspiratory demand of the patient, then thefraction of inspired oxygen is a combination of oxygen provided by thegas source and oxygen due to entrainment of room air.

By way of example and not limitation, if the inspiratory demands of thepatient is PIFR of 30 L/min of room air wherein room air has 21% oxygen,the average FiO2 the patient is receiving or breathing is calculatedwith the following formula: 30 L/min (PIFR) times 21% oxygen of room airis equal to 630 L/min-%, and 630 L/min-% divided by 30 L/min (PIFR) isequal to 21%. The FiO2 the patient is receiving is 21%. The reason isthat 100% of the gas breathed in by the patient is room air which mayhave 21% oxygen.

Now, let's consider an example where the patient is receiving 20 L/minof oxygen via a high flow nasal cannula (HFNC) at a O2 (oxygen)percentage of 100%. The system measures the inspiratory demands of thepatient and the inspiratory demands or PIFR of the patient is 30 L/min.Since the inspiratory demands of the patient is 10 L/min greater thanthe flow rate provided by the gas source, room air is entrained with thesupplied oxygen at a rate of 10 L/min. The system determines theinspiratory demands of the patient, and the flow rate of gas with oxygenat a certain percentage is known. The FiO2 provided to the patient inthis situation may be calculated as follows: (20 L/min times 100%) plus(10 L/min times 21%) is equal to 2210 L/min-%, and 2210 L/min-% dividedby 30 L/min (PIFR) is equal to 73.7% FiO2. The system (e.g., computer)discussed herein may use the determined PIFR of the patient and theknown oxygen percentage of room air to determine the FiO2 received bythe patient.

If the patient has an inspiratory demand of 40 L/min and is still onlyreceiving 20 L/min of supplied oxygen at 100% from the gas source, thenthe FiO2 provided to the patient is as follows: (20 L/min x 100%) plus(20 L/min x 21%)=2420 L/min-%, and 2420 L/min-% divided by 40 L/min(PIFR) is equal to 60.5% FiO2.

In the previous two examples, the nothing changed with the oxygen flowrate being delivered to the patient. Only the patient's PIFR orinspiratory demand changed and the system was capable of determining theFiO2 delivered to the patient due to the dilution of the supplied oxygenfrom the gas source due to entrainment of room air.

The various aspects discussed herein may be implemented when the patientis on a ventilator. Additionally, the various aspects discussed hereinmay be used while treating a patient who has trouble breathing. By wayof example and not limitation, the gas discussed herein which isdelivered to the patient has a certain percentage of oxygen.

The above description is given by way of example, and not limitation.Given the above disclosure, one skilled in the art could devisevariations that are within the scope and spirit of the inventiondisclosed herein. Further, the various features of the embodimentsdisclosed herein can be used alone, or in varying combinations with eachother and are not intended to be limited to the specific combinationdescribed herein. Thus, the scope of the claims is not to be limited bythe illustrated embodiments.

What is claimed is:
 1. A method of administering high-flow oxygentherapy, the method comprising the steps of: providing a respiratorymonitoring system, the respiratory monitoring system comprising: acomputer having: a frame; at least one display coupled to the frame; atleast one processor coupled to the frame; and at least one bioimpedancesensor, the at least one bioimpedance sensor configured to be attachableto a torso of a patient and electrically couplable to the computer, andreceive bioimpedance response from the patient; wherein the respiratorymonitoring system being configured to measure an inspiratory demand ofthe patient based on the bioimpedance response; providing an air-oxygenblender, the air-oxygen blender outputting air deliverable to thepatient by a tube attachable to the patient and to the air-oxygenblender; attaching the at least one bioimpedance sensor to the computerof the respiratory monitoring system and to the patient wherein therespiratory monitoring system receives a signal from the at least onebioimpedance sensor to determine the inspiratory demand of the patientbased on the signal from the at least one bioimpedance sensor and showsthe inspiratory demand on the at least one display; reading theinspiratory demand outputted by the at least one display of therespiratory monitoring system in communication with the computer;determining a peak inspiratory flow rate based on the determinedinspiratory demand; adjusting flow rate of air to be delivered to thepatient from the air-oxygen blender to equal to or greater than thedetermined peak inspiratory flow rate to meet or exceed the inspiratorydemand of the patient; and changing concentration of oxygen in the airdelivered by the air-oxygen blender to increase or decrease oxygeninspired by the patient.
 2. The method of claim 1 wherein therespiratory monitoring system is further configured to determine thepeak inspiratory flow rate and output the peak inspiratory flow rate viathe at least one display of the respiratory monitoring system, andwherein the step of determining peak inspiratory flow rate comprisesreading the peak inspiratory flow rate outputted by the at least onedisplay of the respiratory monitoring system.
 3. The method of claim 1further comprising the steps of attaching the tube to the patient and tothe air-oxygen blender and delivering the air to the patient.
 4. Themethod of claim 3 further comprising determining fraction of oxygeninspired by the patient based on the peak inspiratory flow rate, anunadjusted flow rate of the air being delivered to the patient,concentration of oxygen in the air being delivered to the patient, andflow rate of ambient air inspired by the patient.
 5. The method of claim3 further comprising determining fraction of oxygen inspired by thepatient based on the adjusted flow rate of the air being delivered tothe patient, and concentration of oxygen in the air being delivered tothe patient.
 6. A method of administering high-flow oxygen therapy, themethod comprising the steps of: providing a respiratory monitoringsystem, the respiratory monitoring system comprising: a computer having:a frame; at least one display coupled to the frame; at least oneprocessor coupled to the frame; and at least one bioimpedance sensor,the at least one bioimpedance sensor configured to be attachable to atorso of a patient and electrically couplable to the computer, andreceive bioimpedance response from the patient; wherein the respiratorymonitoring system being configured to measure an inspiratory demand ofthe patient based on the bioimpedance response; providing a breathinggas source, the breathing gas source outputting breathing gasdeliverable to the patient by a tube attachable to the patient and tothe breathing gas source; attaching the at least one bioimpedance sensorto the computer of the respiratory monitoring system and to the patient;attaching the tube to the patient and to the breathing gas source;reading the measured inspiratory demand of the patient, the measuredinspiratory demand of the patient being outputted to the at least onedisplay of the respiratory monitoring system in communication with thecomputer; determining a peak inspiratory demand based on the measuredinspiratory demand; adjusting flow rate of breathing gas to be deliveredto the patient from the breathing gas source to equal to or greater thanthe determined peak inspiratory demand; adjusting concentration ofoxygen of the breathing gas; and delivering the breathing gas to thepatient at the adjusted flow rate and at the adjusted concentration ofoxygen to achieve a target blood oxygen level of the patient.
 7. Themethod of claim 6 wherein the respiratory monitoring system is furtherconfigured to determine the fraction of oxygen inspired by the patientand output the fraction of oxygen inspired by the patient via the atleast one display of the respiratory monitoring system, furthercomprising inputting the adjusted flow rate of the breathing gas beingdelivered to the patient into the respiratory monitoring system.
 8. Themethod of claim 6 wherein the oxygen concentration of the breathing gasis equal to or greater than 21%.
 9. The method of claim 6 wherein thebreathing gas is heated, humidified, and delivered to the patientthrough a nasal cannula.
 10. A respiratory monitoring system used inadministering oxygen therapy, comprising: a computer having: a frame; atleast one display coupled to the frame; at least one processor coupledto the frame; at least one bioimpedance sensor, the at least onebioimpedance sensor configured to be attachable to a torso of a patientand electrically couplable to the computer, and receive bioimpedanceresponse from the patient; wherein the at least one processor isconfigured by program instructions to: determine an inspiratory demandof the patient in real time; and determine a peak inspiratory demand inreal time based on the determined inspiratory demand; and begin flow ofgas to a patient after the instructions to determine the inspiratorydemand of the patient are carried out by the processor; wherein the atleast one display is configured by program instructions to output thedetermined peak inspiratory demand in real time.
 11. The respiratorymonitoring system of claim 10 further comprising a sensor configured todetect flow rate of oxygen being delivered to the patient by an oxygendelivery system.
 12. The respiratory monitoring system of claim 11wherein the at least one processor is further configured by programinstructions to determine fraction of oxygen inspired by the patient inreal time.
 13. The respiratory monitoring system of claim 12 wherein theat least one display is further configured to output the determinedfraction of oxygen inspired by the patient in real time.
 14. Therespiratory monitoring system of claim 10 wherein the at least oneprocessor is further configured by program instructions to determinefraction of oxygen inspired by the patient in real time based on thedetermined peak inspiratory flow rate.
 15. The respiratory monitoringsystem of claim 10 wherein the at least one processor is furtherconfigured by program instructions to communicate with a microcontrollerof an automated oxygen delivery system to adjust flow rate of oxygenbeing delivered to the patient to equal to or greater than thedetermined peak inspiratory demand to meet or exceed the inspiratorydemand of the patient.
 16. The respiratory monitoring system of claim 10wherein the peak inspiratory demand is an estimated peak inspiratoryflow rate, last peak inspiratory flow rate, or greatest peak inspiratoryflow rate.